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我国土壤动物生态地理研究进展 被引量:145
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作者 殷秀琴 宋博 +2 位作者 董炜华 辛未冬 王野乔 《地理学报》 EI CSCD 北大核心 2010年第1期91-102,共12页
通过回顾我国近30年来土壤动物生态地理研究的进展,概述了我国土壤动物群落多样性及生态地理分布。包括我国从热带、亚热带到温带,从森林、草地、沙漠到湿地、农田乃至城市等诸多生态系统。总结了土壤动物群落对环境的响应及其指示意义... 通过回顾我国近30年来土壤动物生态地理研究的进展,概述了我国土壤动物群落多样性及生态地理分布。包括我国从热带、亚热带到温带,从森林、草地、沙漠到湿地、农田乃至城市等诸多生态系统。总结了土壤动物群落对环境的响应及其指示意义研究的相关进展,从土壤动物对环境的营造、净化及其在生态系统凋落物分解和物质循环中的作用三个方面论述了土壤动物的功能,最后介绍了土壤动物与其他生物的互作、地上地下的生态学联系、全球变化对土壤动物群落的影响等热点领域的研究现状,并提出了未来土壤动物生态地理研究的热点问题。包括分子生物技术在土壤动物分类研究中的应用;土壤动物群落多样性的功能和机理;地上与地下生态系统的交互作用;干扰、污染、生物入侵和全球变化对土壤动物群落和功能的影响等。 展开更多
关键词 土壤动物 多样性 功能作用 生态地理 中国
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A review on the eco-geography of soil fauna in China 被引量:94
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作者 YIN Xiuqin SONG Bo +2 位作者 DONG Weihua XIN Weidong WANG Yeqiao 《Journal of Geographical Sciences》 SCIE CSCD 2010年第3期333-346,共14页
This review summarizes main research findings in soil fauna eco-geography in China in the past 30 years. The subject areas and main results were overviewed including biodiversity and eco-geological distribution of soi... This review summarizes main research findings in soil fauna eco-geography in China in the past 30 years. The subject areas and main results were overviewed including biodiversity and eco-geological distribution of soil fauna communities. Studies of ecological distributions of soil fauna and dynamic ranges in space from tropical, subtropical to temperate regions, and in categories from forest, grassland, desert, wetland, farmland to urban ecosystems, the responses and indications of soil fauna to soil environments. Effects of intensive disturbance such as fire, grazing, farming, fertilization on soil fauna include sensitive (e.g. nematode) and rare groups and community indexes. The functions of soil fauna were discussed including environmental construction, environmental purification, litter decomposition and elements cycling. Interactions between soil fauna and other biota in soil ecosystems and linking between aboveground and belowground diversity and the effects of global change on soil fauna community in China were also included. Finally, the authors pointed out common interests in soil fauna eco-geographical studies, which include application of molecule biology into soil fauna taxa; function and mechanism of soil fauna community diversity; interaction between aboveground and belowground ecosystems; effects of disturbance, pollution, biological invasion, and global change on soil fauna community and function. The review is to provide a scientific basis for promoting soil fauna eco-geographical studies in China. 展开更多
关键词 soil fauna BIODIVERSITY BIO-INDICATORS functional role eco-geography
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番茄吸收和积累Cd能力的品种间差异 被引量:46
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作者 朱芳 方炜 杨中艺 《生态学报》 CAS CSCD 北大核心 2006年第12期4071-4081,共11页
旨在筛选和利用在受污染土壤中可食部位污染物积累水平在食品卫生标准允许范围内的农作物品种(pollution-safe cultivar。简称为PSC),以降低水土环境污染物经食物链危害人类健康的风险。研究对象为番茄,探讨了在一定Cd污染土壤中其... 旨在筛选和利用在受污染土壤中可食部位污染物积累水平在食品卫生标准允许范围内的农作物品种(pollution-safe cultivar。简称为PSC),以降低水土环境污染物经食物链危害人类健康的风险。研究对象为番茄,探讨了在一定Cd污染土壤中其果实Cd含量低于国际食品法典委员会(CAC)Cd最高限值的品种(Cd,PSC)存在的可能性。通过盆栽试验研究了36个番茄品种(包括普通番茄和樱桃番茄两个变种)不同器官在受不同程度镉污染的土壤中吸收和积累Cd能力的差异。结果表明:(1)在土壤Cd重度胁迫(13.3mg·kg^-1)和轻度Cd胁迫(1.1mg·kg^-1)下,番茄所有器官Cd含量的变异在统计学上均存在极显著意义(p〈0.01),其中果实Cd含量的范围分别为0.08—0.33mg·kg^-1和0.00—0.09mg·kg^-1,变异系数分别达到28.5%和77.9%;(2)在重度胁迫下,所有供试品种的果实Cd含量均超出CAC标准,而轻度胁迫下的Cd含量超标率达到19.4%。说明番茄是易受Cd污染的农作物种类,其中樱桃番茄的受污染风险特别高,在轻度胁迫下6个供试品种中有5个超标,而30个普通番茄品种仅1个超标。因此。仅在轻度胁迫条件下,存在着番茄的Cd-PSC,其中有5个普通番茄品种的果实中未检出Cd,属于比较安全的PSC,包括品种No.12、16、24、35和№.36,可以推荐在土壤Cd污染程度略超国家三级标准或具有潜在受污染风险的区域应用;(3)尽管大多数情况下各营养器官的Cd含量间均呈显著的正相关。但营养器官与果实Cd含量间均无明显的相关性,推测Cd在番茄营养器官间和营养器官与果实间的转运途径是不一样的。组织中Cd含量的显著相关性说明该特性可以作为农作物品种的种性特征;(4)与轻度胁迫相比,重度胁迫下的所有供试品种平均果实生物量上升了7.5%,一半以上的品� 展开更多
关键词 番茄 受污染土壤 镉积累 品种间差异 食物链污染预防
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Malignant ascites: A review of prognostic factors, pathophysiology and therapeutic measures 被引量:45
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作者 Suma L Sangisetty Thomas J Miner 《World Journal of Gastrointestinal Surgery》 SCIE CAS 2012年第4期87-95,共9页
Malignant ascites indicates the presence of malignant cells in the peritoneal cavity and is a grave prognostic sign. While survival in this patient population is poor, averaging about 20 wk from time of diagnosis, qua... Malignant ascites indicates the presence of malignant cells in the peritoneal cavity and is a grave prognostic sign. While survival in this patient population is poor, averaging about 20 wk from time of diagnosis, quality of life can be improved through palliative procedures. Selecting the appropriate treatment modality remains a careful process, which should take into account potential risks and benefits and the life expectancy of the patient. Traditional therapies, including paracentesis, peritoneovenous shunt placement and diuretics, are successful and effective in varying degrees. After careful review of the patient&#x02019;s primary tumor origin, tumor biology, tumor stage, patient performance status and comorbidities, surgical debulking and intraperitoneal chemotherapy should be considered if the benefit of therapy outweighs the risk of operation because survival curves can be extended and palliation of symptomatic malignant ascites can be achieved in select patients. In patients with peritoneal carcinomatosis who do not qualify for surgical cytoreduction but suffer from the effects of malignant ascites, intraperitoneal chemotherapy can be safely and effectively administered via laparoscopic techniques. Short operative times, short hospital stays, low complication rates and ultimately symptomatic relief are the advantages of laparoscopically administering heated intraperitoneal chemotherapy, making it not only a valuable treatment modality but also the most successful treatment modality for achieving palliative cure of malignant ascites. 展开更多
关键词 CARCINOMATOSIS PERITONEAL PARACENTESIS Peritovenous SHUNTS HIPEC
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Percutaneous microwave ablation vs radiofrequency ablation in the treatment of hepatocellular carcinoma 被引量:41
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作者 Loukia S Poulou Evanthia Botsa +2 位作者 Ioanna Thanou Panayiotis D Ziakas Loukas Thanos 《World Journal of Hepatology》 CAS 2015年第8期1054-1063,共10页
Hepatocellular cancer ranks fifth among cancers and is related to chronic viral hepatitis, alcohol abuse,steatohepatitis and liver autoimmunity. Surgical resection and orthotopic liver transplantation have curative po... Hepatocellular cancer ranks fifth among cancers and is related to chronic viral hepatitis, alcohol abuse,steatohepatitis and liver autoimmunity. Surgical resection and orthotopic liver transplantation have curative potential, but fewer than 20% of patients are suitable candidates. Interventional treatments are offered to the vast majority of patients. Radiofrequency(RFA) and microwave ablation(MWA) are among the therapeutic modalities, with similar indications which include the presence of up to three lesions, smaller than 3 cm in size, and the absence of extrahepatic disease. The therapeutic effect of both methods relies on thermal injury, but MWA uses an electromagnetic field as opposed to electrical current used in RFA. Unlike MWA, the effect of RFA is partially limited by the heat-sink effect and increased impedance of the ablated tissue. Compared with RFA, MWA attains a more predictable ablation zone, permits simultaneous treatment of multiple lesions, and achieves larger coagulation volumes in a shorter procedural time. Major complications of both methods are comparable and infrequent(approximately 2%-3%), and they include haemorrhage, infection/abscess, visceral organ injury, liver failure, and pneumothorax. RFA may incur the additional complication of skin burns. Nevertheless, there is no compelling evidence for differences in clinical outcomes, including local recurrence rates and survival. 展开更多
关键词 Microwave RADIOFREQUENCY Ablation HEPATOCELLULAR CARCINOMA PERCUTANEOUS
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Numerical simulation of strong ground motion for the M_s8.0 Wenchuan earthquake of 12 May 2008 被引量:27
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作者 ZHANG Wei SHEN Yang CHEN XiaoFei 《Science China Earth Sciences》 SCIE EI CAS 2008年第12期1673-1682,共10页
The Wenchuan earthquake of 12 May 2008 is the most destructive earthquake in China in the past 30 years in terms of property damage and human losses. In order to understand the earthquake process and the geo-morpholog... The Wenchuan earthquake of 12 May 2008 is the most destructive earthquake in China in the past 30 years in terms of property damage and human losses. In order to understand the earthquake process and the geo-morphological factors affecting the seismic hazard, we simulated the strong ground mo-tion caused by the earthquake, incorporating three-dimensional (3D) earth structure, finite-fault rupture, and realistic surface topography. The simulated ground motions reveal that the fault rupture and basin structure control the overall pattern of the peak ground shaking. Large peak ground velocity (PGV) is distributed in two narrow areas: one with the largest PGV values is above the hanging wall of the fault and attributed to the locations of fault asperities and rupture directivity; the other is along the north-western margin of the Sichuan Basin and caused by both the directivity of fault rupture and the ampli-fication in the thick sediment basin. Rough topography above the rupture fault causes wave scattering, resulting in significantly larger peak ground motion on the apex of topographic relief than in the valley. Topography and scattering also reduce the wave energy in the forward direction of fault rupture but increase the PGV in other parts of the basin. These results suggest the need for a localized hazard as-sessment in places of rough topography that takes the topographic effects into account. Finally, had the earthquake started at the northeast end of the fault zone and ruptured to the southwest, Chengdu would have suffered a much stronger shaking than it experienced on 12 May, 2008. 展开更多
关键词 WENCHUAN earthquake strong ground motion SEISMIC HAZARD TOPOGRAPHY SEISMIC wave modeling
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Sedimentary records of environmental evolution in the Sanmen Lake Basin and the Yellow River running through the Sanmenxia Gorge eastward into the sea 被引量:26
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作者 王苏民 吴锡浩 +4 位作者 张振克 蒋复初 薛滨 童国榜 田国强 《Science China Earth Sciences》 SCIE EI CAS 2002年第7期595-608,共14页
A series of independent faulted basins developed in the present middle reaches of the Yellow River during late Cenozoic, among which the Sanmen Lake Basin is located in the east edge of the Loess Plateau, a transition... A series of independent faulted basins developed in the present middle reaches of the Yellow River during late Cenozoic, among which the Sanmen Lake Basin is located in the east edge of the Loess Plateau, a transitional zone between the second and third macromorphological step of China. The thick strata of the Sanmen Group deposited in the large basin. The Sanmen Group is a perfect place for the study on paleoenvironmental change, tectono-climatic cycles as well as the formation and evolution of the Yellow River. In this paper, the paleoenvironmental changes, regional tectonic movement and the evolutionary process of the Sanmen Lake Basin during the past 5 Ma were reconstructed based on the analysis of paleomagnetic stratigraphy, pollen, TOC and carbonate content from the Huangdigou outcrop near the Sanmenxia Reservoir, Pinglu County, Shanxi Province. The sedimentary records from the outcrop indicate that the basin was first formated by fault activity at about 5.4 MaBP, and after the strong tectonic movement at 3.6 MaBP the lake enlarged and the rainfall of summer monsoon increased. There was no great climatic transition near 2.6 MaBP, corresponding to the bottom age of loess in the Loess Plateau. After Olduvai event (about 1.77 MaBP) the Picea and Abies were presented in the sediments, which indicates a colder climate. The tectonic movement at 1.2 MaBP caused the light angular discordance between the upper and lower Sanmen Group. The sedimentary records show a cold and wet climate during the prosperous periods of loess accumulation such as L15, L9, L6. The tectonic intensification periods of the Sanmen Basin correspond with the tectonic movements in the Qinghai-Xizang Plateau chronologically. The earliest age of the outflow from the Paleo-Sanmen Lake or the partly cutting off of the Sanmenxia Gorge was about 0.41- 0.35 MaBP. The age of cutting thoroughly the Sanmenxia Gorge by the Yellow River and the disappearance of the Paleo-Sanmen Lake was about 0.15 MaBP, which symbolized the formation of the present Yellow 展开更多
关键词 Sanmen Basin sedimentary records formation of the Yellow River environmental evolution tectono-climatic cycles
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基于全文内容的学术论文研究方法自动分类研究 被引量:25
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作者 章成志 李卓 储荷婷 《情报学报》 CSSCI CSCD 北大核心 2020年第8期852-862,共11页
对学术论文所采用的研究方法进行自动分类,有助于研究方法使用行为的分析与研究方法的评估,进而为科研人员推荐或选择合适的研究方法提供依据。相比于摘要信息,全文内容包含更多关于研究方法的上下文信息,因此探索基于全文内容的学术论... 对学术论文所采用的研究方法进行自动分类,有助于研究方法使用行为的分析与研究方法的评估,进而为科研人员推荐或选择合适的研究方法提供依据。相比于摘要信息,全文内容包含更多关于研究方法的上下文信息,因此探索基于全文内容的学术论文研究方法自动分类具有重要的意义。本研究以图书情报领域的820篇学术论文全文为研究对象,邀请专家对其研究方法进行标注得到研究方法训练语料;采用多标签分类任务中问题转换法和算法自适应法,将朴素贝叶斯与支持向量机作为问题转换法的底层分类器,构建6种不同的分类模型,同时选用算法自适应法中的ML-KNN模型,分别对论文中使用的研究方法进行自动分类。实验结果表明,相较于学术论文的摘要信息,全文内容在研究方法分类的性能上有较大的提升;朴素贝叶斯算法在问题转换法的分类器链策略中表现最佳,F1值达到0.705;另外结果也表明不同的学术论文研究方法的特征表征能力不同,训练集的规模较少会导致分类的泛化效果差。 展开更多
关键词 研究方法分类 文本分类 全文内容 多标签分类
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Schistosoma japonicum infection induces macrophage polarization 被引量:22
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作者 Jingwei Xu Hao Zhang +4 位作者 Lin Chen Donghui Zhang Minjun Ji Haiwei Wu Guanling Wu 《The Journal of Biomedical Research》 CAS 2014年第4期299-308,共10页
The role of macrophages (MФ) as the first line of host defense is well accepted. These cells play a central role in orchestrating crucial functions during schistosomal infection. Thus, understanding the functional ... The role of macrophages (MФ) as the first line of host defense is well accepted. These cells play a central role in orchestrating crucial functions during schistosomal infection. Thus, understanding the functional diversity of these cells in the process of infection as well as the mechanisms underlying these events is crucial for developing disease control strategies. In this study, we adopted a Mqb polarization recognition system. M1 macrophage was characterized by expressing CD16/32, IL-12 and iNOS. M2 macrophage was characterized by expressing CD206, IL-10 and arg-1. In vivo (mouse peritoneal macrophages of different infection stages were obtained) and in vitro (different S. japonicum antigens were used to stimulate RAW264.7) were characterized by using the above mentioned system. NCA and ACA stimulated RAW264.7 express significantly higher levels of IL-12 while significantly higher levels of IL-10 were detected after soluble egg antigen (SEA) stimulation. The results showed that dramatic changes of antigen in the microenvironment before and after egg production led to macrophage polarization. Furthermore, through TLR blocking experiments, the TLR4 signaling pathway was found to play a role in the process of macrophage polarization toward M1. Our data suggest that macrophage polarization during S. japonicum infection had significant effects on host immune responses to S. japonicum. 展开更多
关键词 MACROPHAGE polarization schistosome japonicum TLRS
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The Optimal Design of TMD for Offshore Structures 被引量:18
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作者 Sau Lon James HU Tomotsuka TAKAYAMA 《China Ocean Engineering》 SCIE EI 1999年第2期133-144,共12页
This paper presents the optimal design procedure of Tuned Mass Damper (TMD) for reducing vibration of an actual steel jacket offshore platform excited by random wave loading. In this study, a frequency domain is taken... This paper presents the optimal design procedure of Tuned Mass Damper (TMD) for reducing vibration of an actual steel jacket offshore platform excited by random wave loading. In this study, a frequency domain is taken. The force on the structure is determined by use of the linearized Morison equation for an input Power Spectral Density (PSD) of wave elevation. The sensitivity of optimum values of TMD to characteristic parameters of random wave spectrum is analyzed. An optimized TMD design for the modeled platform is given based on design conditions and the findings of the study. 展开更多
关键词 tuned mass damper DESIGN Morison equation power spectral density offshore structures
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Hypoalbuminemia in colorectal cancer prognosis:Nutritional marker or inflammatory surrogate? 被引量:23
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作者 Bassel Nazha Elias Moussaly +2 位作者 Mazen Zaarour Chanudi Weerasinghe Basem Azab 《World Journal of Gastrointestinal Surgery》 SCIE CAS 2015年第12期370-377,共8页
Albumin is the single most abundant protein in the human serum. Its roles in physiology and pathology are diverse. Serum albumin levels have been classically thought to reflect the nutritional status of patients. This... Albumin is the single most abundant protein in the human serum. Its roles in physiology and pathology are diverse. Serum albumin levels have been classically thought to reflect the nutritional status of patients. This concept has been challenged in the last two decades as multiple factors, such as inflammation, appeared to affect albumin levels independent of nutrition. In general, cancer patients have a high prevalence of hypoalbuminemia. As such, the role of hypoalbuminemia in patients with colorectal cancer has received significant interest. We reviewed the English literature on the prognostic value of pretreatment albumin levels in colorectal cancer. We also consolidated the evidence that led to the current understanding of hypoalbuminemia as an inflammatory marker rather than as a nutritional one among patients with colorectal cancer. 展开更多
关键词 HYPOALBUMINEMIA ALBUMIN COLORECTALCANCER Albumin-to-globulin ratio Cancer survival Systemic INFLAMMATORY response GLASGOW prognosticscore
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The landscape of aging 被引量:22
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作者 Yusheng Cai Wei Song +50 位作者 Jiaming Li Ying Jing Chuqian Liang Liyuan Zhang Xia Zhang Wenhui Zhang Beibei Liu Yongpan An Jingyi Li Baixue Tang Siyu Pei Xueying Wu Yuxuan Liu Cheng-Le Zhuang Yilin Ying Xuefeng Dou Yu Chen Fu-Hui Xiao Dingfeng Li Ruici Yang Ya Zhao Yang Wang Lihui Wang Yujing Li Shuai Ma Si Wang Xiaoyuan Song Jie Ren Liang Zhang Jun Wang Weiqi Zhang Zhengwei Xie Jing Qu Jianwei Wang Yichuan Xiao Ye Tian Gelin Wang Ping Hu Jing Ye Yu Sun Zhiyong Mao Qing-Peng Kong Qiang Liu Weiguo Zou Xiao-Li Tian Zhi-Xiong Xiao Yong Liu Jun-Ping Liu Moshi Song Jing-Dong J.Han Guang-Hui Liu 《Science China(Life Sciences)》 SCIE CAS CSCD 2022年第12期2354-2454,共101页
Aging is characterized by a progressive deterioration of physiological integrity,leading to impaired functional ability and ultimately increased susceptibility to death.It is a major risk factor for chronic human dise... Aging is characterized by a progressive deterioration of physiological integrity,leading to impaired functional ability and ultimately increased susceptibility to death.It is a major risk factor for chronic human diseases,including cardiovascular disease,diabetes,neurological degeneration,and cancer.Therefore,the growing emphasis on “healthy aging” raises a series of important questions in life and social sciences.In recent years,there has been unprecedented progress in aging research,particularly the discovery that the rate of aging is at least partly controlled by evolutionarily conserved genetic pathways and biological processes.In an attempt to bring full-fledged understanding to both the aging process and age-associated diseases,we review the descriptive,conceptual,and interventive aspects of the landscape of aging composed of a number of layers at the cellular,tissue,organ,organ system,and organismal levels. 展开更多
关键词 AGING MECHANISM INTERVENTION
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Identifying sources and hazardous risks of heavy metals in topsoils of rapidly urbanizing East China 被引量:22
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作者 刘洋 马宗伟 +1 位作者 吕建树 毕军 《Journal of Geographical Sciences》 SCIE CSCD 2016年第6期735-749,共15页
With rapid economic and social development, soil contamination arising from heavy metals has become a serious problem in many parts of China. We collected a total of 445 samples (0-20 cm) at the nodes of a 2 kmx2 km... With rapid economic and social development, soil contamination arising from heavy metals has become a serious problem in many parts of China. We collected a total of 445 samples (0-20 cm) at the nodes of a 2 kmx2 km grid in surface soils of Rizhao city, and analyzed sources and risk pattern of 10 heavy metals (As, Cd, Co, Cr, Cu, Hg, Mn, Ni, Pb and Zn). The combination of Multivariate statistics analysis and Geostatistical methods was applied to identify the sources and hazardous risk of heavy metals in soils. The result indicated that Cr, Ni, Co, Mn, Cu, and As were mainly controlled by parent materials and came from natural sources. Cd and Hg originated from anthropogenic sources. Pb and Zn, belonging to different groups in multivariate analysis, were associated with joint effect of parent materials and human inputs. Ordinary Kriging and Indicator Kriging suggested that single element and elements association from the same principal components had similar spatial distribution. Through comprehensive assessment on all elements, we also found the high risk areas were located in the populated urban areas and western study area, which could be attributed to the higher geological background in the western part and strong human interference in the eastern part. 展开更多
关键词 heavy metals in soils hazardous risk multivariate analysis Indicator Kriging Rizhao
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Multiple-Step Predictive Control for Offshore Structures 被引量:14
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作者 李华军 Sau-Lon JAMES HU 《China Ocean Engineering》 SCIE EI 1999年第3期231-246,共16页
Ocean wave propagation is slow, visible and measurable, so a wave theory can be used to approximately predict the imminnent wave force on an offshore structure based on measured, real-time wave elevation near the stru... Ocean wave propagation is slow, visible and measurable, so a wave theory can be used to approximately predict the imminnent wave force on an offshore structure based on measured, real-time wave elevation near the structure. This predictability suggests the development of a more efficient algorithm, than those that have been developed for structures under wind and seismic loads, for the active vibration control of offshore structures. The present study delveops a mutiple-step predictive optimal control (MPOC) algorithm that accounts for multiple step external loading in the determination of optimal control forces. The control efficiency of the newly developed MPOC algorithm has been Investigated under both regular (single-frequency) and irregular (multiple-frequency) wave loads, and compared with that of two other well-known optimal control algorithms: classical linear optimal control(CLOC) and instantaneous optimal control(IOC). 展开更多
关键词 active control offshore structure predictive control control algorithm wave load VIBRATION
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The Ozone Component of Global Change:Potential Effects on Agricultural and Horticultural Plant Yield,Product Quality and Interactions with Invasive Species 被引量:19
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作者 Fitzgerald Booker Russell Muntifering +7 位作者 Margaret McGrath Kent Burkey Dennis Decoteau Edwin Fiscus William Manning Sagar Krupa Arthur Chappelka David Grantz 《Journal of Integrative Plant Biology》 SCIE CAS CSCD 2009年第4期337-351,共15页
The productivity, product quality and competitive ability of important agricultural and horticultural plants in many regions of the world may be adversely affected by current and anticipated concentrations of ground-l... The productivity, product quality and competitive ability of important agricultural and horticultural plants in many regions of the world may be adversely affected by current and anticipated concentrations of ground-level ozone (O_3). Exposure to elevated O_3 typically results in suppressed photosynthesis, accelerated senescence, decreased growth and lower yields. Various approaches used to evaluate O_3 effects generally concur that current yield losses range from 5% to 15% among sensitive plants. There is, however, considerable genetic variability in plant responses to O_3. 展开更多
关键词 climate change CROP FORAGE horticultural plant OZONE product quality weedyield.
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二维各向异性介质中地震波场的高阶同位网格有限差分模拟 被引量:18
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作者 祝贺君 张伟 陈晓非 《地球物理学报》 SCIE EI CAS CSCD 北大核心 2009年第6期1536-1546,共11页
本文将DRP/opt MacCormack有限差分格式用于模拟二维各向异性介质中的地震波传播.DRP/optMacCorma ck是一种同位网格下的差分格式,避免了传统的交错网格在计算各向异性问题时由于变量插值而导致的误差.而且相对于低阶同位网格差分格式,... 本文将DRP/opt MacCormack有限差分格式用于模拟二维各向异性介质中的地震波传播.DRP/optMacCorma ck是一种同位网格下的差分格式,避免了传统的交错网格在计算各向异性问题时由于变量插值而导致的误差.而且相对于低阶同位网格差分格式,它具有低色散、低耗散的优点.此格式将中心差分算子分成前向和后向两个空间单边差分,然后在4-6步Runge-Kutta时间积分中使用单边差分组合.在具有垂直对称轴的横向各向同性(VTI)模型下,通过对比DRP/opt MacCormack有限差分和谱元方法的模拟结果,验证了前者具有很高的精度和稳定性.由于实际地质条件下TI介质的对称轴通常是倾斜的(TTI),本文在二维三分量框架下模拟TTI介质中的地震波场.结果显示横波分裂和切平面/反平面运动耦合的特征.数值实验表明DRP/opt MacCormack是一种有效的研究各向异性介质中地震波传播规律的差分格式. 展开更多
关键词 有限差分 DRP/opt MacCormack格式 理论地震图 各向异性 TTI介质
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外科手术中产生的烟气:仅仅是大量的热空气吗? 被引量:17
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作者 Barrett WL Garber SM +1 位作者 黄文海 朱江帆(摘译) 《中国微创外科杂志》 CSCD 2005年第4期263-265,共3页
外科医生和手术室人员经常接触手术设备产生的烟气,病人也会暴露于烟气中,特别是腹腔镜手术中产生的烟气滞留于腹腔内这一密闭空间并被吸收。这些烟气是一种与香烟烟气相似的毒性物质,然而对这种毒性物质的影响还未引起足够重视。应该... 外科医生和手术室人员经常接触手术设备产生的烟气,病人也会暴露于烟气中,特别是腹腔镜手术中产生的烟气滞留于腹腔内这一密闭空间并被吸收。这些烟气是一种与香烟烟气相似的毒性物质,然而对这种毒性物质的影响还未引起足够重视。应该采取必要措施尽可能减少手术中烟气的不良影响。 展开更多
关键词 职业性危害 烟雾 组织切除 电刀 激光刀 超声刀
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Optimal Active Control of Wave-Induced Vibration for Offshore Platforms 被引量:10
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作者 李华军 Sau-LonJamesHU TomotsukaTAKAYAMA 《China Ocean Engineering》 SCIE EI 2001年第1期1-14,共14页
An obvious motivation of this paper is to examine the effectiveness of the lateral vibration control of a jacket type offshore platform with an AMD control device, in conjunction with H-2 control algorithm, which is a... An obvious motivation of this paper is to examine the effectiveness of the lateral vibration control of a jacket type offshore platform with an AMD control device, in conjunction with H-2 control algorithm, which is an optimal frequency domain control method based on minimization of H-2 norm of the system transfer function In this study, the offshore platform is modeled numerically by use of the finite element method, instead of a lumped mass model This structural model is later simplified to be single-degree-of-freedom (SDOF) system by extracting the first vibration mode of the structure. The corresponding 'generalized' wave force is determined based on an analytical approximation of the first mode shape function, the physical wave loading being calculated from the linearized Morison equation. This approach facilitates the filter design for the generalized force. Furthermore, the present paper also intends to make numerical comparison between H-2 active control and the corresponding passive control using a TMD with the same device parameters. 展开更多
关键词 active control offshore platform VIBRATION wave loading
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Role of Nrf2 in chronic liver disease 被引量:17
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作者 Wei Tang Yong-Fang Jiang +1 位作者 Murugavel Ponnusamy Mamadou Diallo 《World Journal of Gastroenterology》 SCIE CAS 2014年第36期13079-13087,共9页
Nuclear erythroid 2-related factor 2(Nrf2) is a central regulator of antioxidative response elements-mediated gene expression. It has a significant role in adaptive responses to oxidative stress by interacting with th... Nuclear erythroid 2-related factor 2(Nrf2) is a central regulator of antioxidative response elements-mediated gene expression. It has a significant role in adaptive responses to oxidative stress by interacting with the antioxidant response element, which induces the expression of a variety of downstream targets aimed at cytoprotection. Previous studies suggested oxidative stress and associated damage could represent a common link between different forms of diseases. Oxidative stress has been implicated in various liver diseases, including viral hepatitis, nonalcoholic fatty liver disease/steatohepatitis, alcoholic liver disease and drug-induced liver injury. Nrf2 activation is initiated by oxidative or electrophilic stress, and aids in the detoxification and elimination of potentially harmful exogenous chemicals and their metabolites. The expression of Nrf2 has been observed throughout human tissue, with high expression in detoxification organs, especially the liver. Thus, Nrf2 may serve as a major regulator of several cellular defense associated pathways by which hepatic cells combat oxidative stress. We review the relevant literature concerning the crucial role of Nrf2 and its signaling pathways against oxidative stress to protect hepatic cell from oxidative damage during development of common chronic liver diseases. We also review the use of Nrf2 as a therapeutic target to prevent and treat liver diseases. 展开更多
关键词 Nuclear erythroid 2-related factor 2 Chronic liver disease Oxidative stress Reactive oxygen species Hepatic injury Hepatic protection
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High-resolution data collection for analysis of sediment dynamic processes associatedwith combined current-wave action over intertidal flats 被引量:17
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作者 WANG Yaping GAO Shu JIA Jianjun 《Chinese Science Bulletin》 SCIE EI CAS 2006年第7期866-877,共12页
An MIDAS-400 Customised Data Ac- quisition System was deployed to obtain current ve- locity and suspended sediment concentration profiles over the intertidal flat at Wanggang, on the Jiangsu coast (China). At the same... An MIDAS-400 Customised Data Ac- quisition System was deployed to obtain current ve- locity and suspended sediment concentration profiles over the intertidal flat at Wanggang, on the Jiangsu coast (China). At the same time, seawater tempera- ture, conductivity and pressure were measured. Us- ing a data sampling rate of 4 Hz, the high-frequency pressure signals in response to water surface fluc- tuations were recorded and subsequently trans- formed into wave parameters. The analytical results show that the apparent bed roughness length has a magnitude close to the height of sand ripples, which is much larger than the grain size diameter. The bot- tom shear stress associated with current-wave in- teraction is higher than the tidally-induced stress and intensified turbulent mixing and resuspension. Fur- thermore, several suspended sediment concentration peaks occurred during a tidal cycle, which can be related to strong turbulence near the bed caused by frontal tidal currents and the enhanced resuspension; advection and extreme weather conditions (e. g. storms and strong winds) also played an important role. Finally, large net suspended sediment fluxes were observed to present when the flood or ebb currents prolonged, i.e. the flow became quasi-unid- irectional during a tidal cycle. In general, the MIDAS- 400 is a suitable tool for high-resolution data collec- tion for the situations of combined current-wave ac- tion over intertidal flats; the data obtained can be used to analyze the processes and mechanisms of material transport. 展开更多
关键词 高分辨率数据收集 底板压力 悬浮 沉积 浓缩 潮间带
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